It is well known to arrange telecommunications equipment in shelf assemblies. In some shelf assemblies, circuit cards are removably connected to a backplane or midplane. The circuit cards may be arranged in parallel to one another and may be guided to be perpendicular to the backplane or midplane. Electrical connections are established between connectors on the backplane or midplane and complementary connectors on the back edge of each circuit card. Typically, the connectors include multiple pins and sockets arranged in one or more rows along part or all of the back edge of the circuit card. When a circuit card is inserted into the equipment shelf, the shelf guides provide an approximate alignment for the pins and sockets, and a precise alignment is achieved by the mating portions of the connectors.
The backplane or midplane typically provides power to each circuit card, as well as electrical interconnections between circuit cards. The electrical signal assigned to each connector pin is left to the designer of the card and chassis to decide. Thus, various connector pin-outs have been developed, both industry standard and proprietary. The PCI Industrial Computer Manufacturers Group (PICMG) 3.0 specification defines an open architecture whereby circuit cards from different manufacturers can interoperate within a shelf assembly. The PICMG specification defines the pinout and function of the various connectors used to connect a circuit card to the midplane of a shelf assembly.
FIG. 1 is a perspective view of the basic elements of a PICMG 3.0 compliant card assembly platform. In FIG. 1, front board 101 contains the electrical components required to perform a desired function or application and has connectors required to interface with a shelf midplane 103. The PICMG standard defines three connector zones on front board 101. Zone 1 provides power connection and shelf management, Zone 2 provides the data transport interface, and Zone 3 permits a user defined input/output interconnect. Midplane 103 has connector interfaces for the Zone 1 and Zone 2 connectors on the front board 101, as well as mechanical alignment and support. Rear transition module 105 provides user defined input and output connectivity between the Zone 3 connector on the front board 101 and external systems or devices.
Shelf assemblies permit the deployment of several application cards in a comparatively small space. In many shelf architectures, a shelf management interface card is provided to monitor shelf status and provide the ability to manage cards within the shelf, for example by relaying network management queries and responses between a system manager and an application card. A common network management protocol is Simple Network Management Protocol (SNMP), which typically uses TCP/IP for transport. Thus, in order for the application card to receive and respond to SNMP queries, the application card must be functioning at a level that permits communication at a higher-level protocol. For example, the operating system on an application card must generally be operational to implement SNMP or another application level management protocol. When a card fails on booting up, the operating system may not be available. As a result, application level management functions are typically not available.
In order to provide diagnostic and management connectivity when application level management capabilities are not available, application cards have typically included a dedicated serial port to permit configuring and debugging the application card when the application card is not capable of supporting a higher level protocol. This dedicated serial port is referred to as a console port. The console port is generally accessible through rear transition module 105 using a suitable connector. Requiring a dedicated console port on each card increases the cost of electronic equipment assemblies when the assemblies have multiple cards. In addition, the time and equipment required to diagnose card failures is increased since the console port on each card must be accessed in order to monitor data being sent from each card.
Accordingly, there exists a need for improved methods and systems for providing diagnostic and management connectivity to application cards in electronic equipment assemblies having multiple application cards.